Arius

Arius is a wealthy, insane businessman who serves as the primary antagonist of Devil May Cry 2. Although he is the president of an international public corporation "Uroboros", he focuses his research into the black arts as a modern-day sorcerer, in an effort to raise the demon known as Argosax from the Demon World and use its power to become "an all-powerful immortal". He came to Dumary Island in search of the legendary Arcana, the four mystical artifacts which would allow him to unseal Argosax.

Description
Arius has a somewhat refined manner, dressing in expensive clothes and generally behaving with great composure. His most distinctive trait is his obsession with power. Although he is already a powerful sorcerer, as well as the wealthy president of an international enterprise, his ultimate goal is nothing less than to become an immortal god.

Devil May Cry 2
Dante first learns of Arius when he goes to Dumary Island at the request of Lucia, a Devil hunter with Demonic powers. Her mother Matier tells Dante that decades ago, Arius and his company Uroboros transformed their beloved homeland to a Demonic nest under the facade of building a modern city and mining for ore, and asks Dante to deal with the sorcerer and his master.

Lucia and Dante soon spot Arius flying away in his helicopter, and Lucia is the first to catch up to him at the helicopter landing pad on the off-shore oil rig. Arius comments that "the defect is back", and reveals that Lucia is not one of the Vie de Marli, but rather a defective Secretary Demon: Matier merely found Lucia just before she was to be disposed of, and raised her as a warrior. Lucia shouts that he is lying and attacks Arius, but Arius merely cuts open her sleeves, revealing a "Χ" (chi) on her shoulder as proof of his claim. He demands that Lucia give him the Arcana, so that he can become immortal, and when Lucia refuses, he teleports her to a Demonic nest in the Ruin. Dante arrives at the helicopter pad shortly afterward, but Arius merely summons Furiataurus to fight the Devil hunter as he escapes on his helicopter.

After finding the last of the Arcana, Lucia gives them to Dante to deliver to Matier, and sets off to the Uroboros headquarters to take down Arius. Disguised as a Secretary, she manages to make it to his office, but he is not deceived, and spitefully asks if she has come back to rejoin him. She attacks, but is unable to defeat Arius and is captured. Dante soon arrives to rescue Lucia, and seemingly hands over the Arcana. He attacks, and although he is unable to kill Arius, he is able to rescue Lucia and fly to safety using his Devil Trigger.

Both of the Devil hunters return to the building, using a magical portal to enter through the Demon World, but by the time they arrive the sun has already eclipsed, and Arius has been able to start the summoning. However, the ritual backfires, as Dante had replaced the Arcana Medaglia with his own, mundane coin. This time, Dante is able to defeat Arius, and shoots him in the head at point-blank range. However, although the ritual was interrupted, it still opens a portal to the Demon World, and Dante goes through to finish off the Demon, Argosax, that Arius was attempting to summon.

At the same time, Arius revives due to Argosax's influence, transformed into a mindless, tentacled demon named "Possessed Arius". Lucia fights him back, and he draws on the power of Argosax to mutate further into "Arius-Argosax". In the end though, Lucia slays the monster, just as Dante finishes off Argosax and the rift closes.

Powers & Abilities
Arius's study of the dark arts has given him access to a multitude of powerful spells, such as magical barriers and teleportation, granting himself superhuman resilience and vitality, as well as the ability to summon or create various lesser demons, such as Furiataurus or his own creations, the Secretaries. Despite his magical powers, he also uses a personal revolver to fight his opponents. After becoming possessed by the essence of Argosax, Arius' size and strength were increased. He utilizes dark powers manifested through black vortex which can be for summoning demons, spawn shadowy magical spikes and even engulf its foes to later catapult them.

Background
Arius was a third-century Christian priest who was deemed a heretic due to his assertion that Christ the Son was not eternal, and had not existed before he was begotten.

Trivia

 * Arius' facial features were inspired by the villain of For a Few Dollars More played by actor Lee van Cleef.
 * When Matier meets Dante, she requests to "handle Arius and his master". This seems to imply that Arius was already influenced in some way by Argosax before ever performing the ritual. His further degradation into demonhood due to Argosax's powers seem to confirm this.